/*
 Problem Description
A number sequence is defined as follows:

f(1) = 1, f(2) = 1, f(n) = (A * f(n - 1) + B * f(n - 2)) mod 7.

Given A, B, and n, you are to calculate the value of f(n).
 

Input
The input consists of multiple test cases. Each test case contains 3 integers A, B and n on a single line (1 <= A, B <= 1000, 1 <= n <= 100,000,000). Three zeros signal the end of input and this test case is not to be processed.
 

Output
For each test case, print the value of f(n) on a single line.
 

Sample Input
1 1 3
1 2 10
0 0 0
 

Sample Output
2
5
 */
package com.yuan.algorithms.acm201505;

import java.util.Scanner;

public class HD1005 {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		while(sc.hasNext()) {
			int a = sc.nextInt();
			int b = sc.nextInt();
			int n = sc.nextInt();
			if (a==0 && b==0 && n==0) {
				break;
			}
			int[]arr = new int[1009];
			arr[1]=1;arr[2] = 1;
			for (int i = 3; i < arr.length; i++) {
				arr[i] = (arr[i-1] * a + arr[i-2]*b)%7;
			}
			System.out.println(arr[(n-1)%1008+1]);
		}

	}

}
